Showing papers in "Geothermics in 2006"

TL;DR: In this article, the authors evaluated thermophysical properties and performed numerical simulations to explore the fluid dynamics and heat transfer issues in an engineered geothermal reservoir that would be operated with CO2.

TL;DR: The results and conclusions drawn from tracer tests performed in 2000-2005 during hydraulic stimulation operations and a short-term circulation test in wells GPK-2, GPK -3 and GPK 4 were discussed in this paper.

TL;DR: McDermott et al. as discussed by the authors used an experimentally validated geomechanical model for fracture deformation under hydraulic, mechanical and thermal loads, and showed that preferential fluid flow paths and shortcuts may develop, depending on the mechanical deformation and thermal stress releases that occur during intense exploitation of these systems.

TL;DR: In this paper, the effect on the transport properties of fractures of a relative shear displacement of rough walls with complementary self-affine surfaces has been studied experimentally and numerically.

TL;DR: The petrographic model for the deep-seated geology at the Soultz-sous-Forets Enhanced Geothermal System (EGS) site in the Rhine Graben, France, was revised on the basis of data from 5 km-deep wells as mentioned in this paper.

TL;DR: In this article, carbon dioxide fluxes were measured across the Rotorua geothermal system in the Taupo Volcanic Zone (TVZ), New Zealand during 2002 and 2003, and the results of a 956-measurement survey and of modeling studies show that CO 2 fluxes could be used to determine the main hot fluid upflow areas, and perhaps in undeveloped geothermal regions.

TL;DR: In this paper, a general model developed from fractal modeling of a porous medium was applied and found to match the capillary pressure curves of The Geysers rocks satisfactorily.

TL;DR: In this article, a numerical study of the coupling between forced and free convective flows has been performed by considering a large range of injection rates and Rayleigh numbers, showing that if there is weak or no free convection in an EGS reservoir, economic exploitation of the system will rapidly end because of a decrease in produced fluid temperature.

TL;DR: In this paper, the authors applied the stress components to the nodal planes of several events and were able to determine their fault plane and obtain a 3D image of the fracture network, based on real data.

TL;DR: In this article, a thermo-hydraulic-chemical coupled computer code was developed specifically to predict changes in the geothermal reservoir of the Soultz-sous-Forets Enhanced Geothermal System (EGS) located in Alsace, France.

TL;DR: In this article, a comparison between the fluids from Dixie valley springs, fumaroles, and wells and the fluids produced from the geothermal field reveals a mixing trend between geothermal fluid and younger, cooler groundwaters.

TL;DR: The rare earth elements (REE) concentrations in the waters of Obuki hot spring, Tamagawa geothermal system, Akita Prefecture, Japan, have been determined in order to investigate their long-term variations over a 30-year period.

TL;DR: In this paper, a comparison between the petrophysical properties of the rock and the interpretation of the hydraulic test results is proposed as a means of determining the distribution of the natural permeable fractures.

TL;DR: In this article, a detailed analysis of geothermal fields of Berl´ on and Ahuachap´ an has revealed important volcano-structural and petrologic differences between the two areas.

TL;DR: In this article, the authors proposed a method for finding discontinuous solutions and an equation for the velocity of the thermal front in a geothermal reservoir by assuming the rock density and heat capacity of the water-rock system as functions of temperature.

TL;DR: In this paper, self-potential (SP), magnetic and very low frequency electromagnetic (EM-VLF) surveys were carried out in the Seferihisar geothermal area to identify major and minor fault zones and characterize the geothermal system.

TL;DR: In this paper, the chemical and temperature conditions prevailing in the Las Tres Virgenes (LTV) geothermal field, Mexico, were estimated, including their central tendency and dispersion parameters, based on geochemical data on waters from springs and domestic wells, and on geothermal well fluids (waters and gases).

TL;DR: In this article, a numerical model based on a discrete fracture network approach has been written to interpret and predict the pressure distribution in the European hot dry rock project (HDR) at Soultz-sous-Forets (France).

TL;DR: In this article, measurements of the periodic transient flow in a vertical geysering geothermal well are presented, and a one-dimensional numerical model of the flow has been developed.

TL;DR: Zhang et al. as discussed by the authors used double-difference tomography to estimate the 3D seismic velocity structure of the Soultz-sous-Forets Hot Dry Rock (HDR) site, Alsace, France.

TL;DR: The potential for hydrothermal eruptions, which could be triggered by reducing hydrostatic pressures, was tested by stepwise dewatering of two, max. 10,000 m2, artificial ponds.

TL;DR: The Hot Dry Rock economic (HDRec) as mentioned in this paper is a costbenefit analysis program for geothermal projects that combines economic aspects with the technical characteristics of the surface installations and the hydrogeological and thermal properties of the subsurface.

TL;DR: In this paper, a method for predicting the distribution of temperatures in geothermal areas using the neuronet approach and, in particular, downhole temperature logs is proposed, which is tested against the results of an analytical model, showing that the errors in neuronet temperature estimates based on well log data derive from: (a) the neur-onet "education level" (which depends on the amount and structure of information used for teaching) and (b) the distance of the point at which the estimate is made from the area for which data are available.

TL;DR: In this paper, a numerical model was developed and validated to simulate the thermal behavior of an open pond, based on hourly temperature measurements collected from various depths and at various sites in the pond during the last heating period.

TL;DR: Experimental measurements of fouling resistance were carried out in a double-pipe heat exchanger (HE), with geothermal water flowing in the inner tube and tap water in the annular space.

TL;DR: In this article, the authors examined the thermal waters of the Idaho batholith to verify whether maximum system temperatures, helium concentrations, and 14 C values are related to water age in these low-to-moderate temperature geothermal systems.

TL;DR: In this paper, the effects of this injection were estimated using measured hydraulic and microseismic data, and the results indicated that the brine had no effect on the fractures in GPK3.

TL;DR: In this article, particle tracking was used for the analysis of heat transport in injection-production doublets if pumping rates are sufficiently high relative to well spacing and aquifer thickness, and particle tracking may provide a cost and time-efficient alternative method for estimating production well temperatures.

TL;DR: In this article, the influence of brine density data on the assessment of pumping requirements for geothermal installations is evaluated. But the results show large discrepancies between the different references, which lead to severe inaccuracies in the evaluation of the buoyancy effect, and thus of the pumping requirements.